1953 Puerto Rico highway renumbering
In 1953, the Puerto Rico Department of Transportation and Public Works implemented a major renumbering of its insular highways. Before 1953, highway routes were numbered in the 1 to just over 100 range and were distributed randomly throughout the island, resulting in several routes with long road lengths.
Source: Wikipedia — 1953 Puerto Rico highway renumbering (CC BY-SA 4.0)